Reducing pond size?

[woolly]

Hi, new here. I inherited a pond 18 months ago, and after living with it for a while we are thinking about reducing the size of it. Currently it takes up 50% of a relatively small garden, is mostly 'natural', and I estimate is around 25,000 litres (one end is intended as a plunge pool, about one and half metres deep approx. I've had conflicting advice from professionals - one that doing so would destroy the equilibrium so it's all or nothing; and one that says a pond can easily be partially filled in and my pond is not in equilibrium anyway with no oxygenating plants (true, and the water quality has indeed deteriorated over the last year).

Does anyone have any thoughts about reducing the size? Advice? Whether to keep the deep end or the shallow end, or the bit inbetween? (the shallow end is very shallow and would be a nightmare to maintain alone I think, would perhaps have to be re-invented as an ornamental pond and the fish certainly re-homed. We do love the nature part of it, always get lots of frogs etc. Pic attached if that helps (note the decked area in the second pic is now lawn).

Thanks in advance!

 

[MitchM]

Welcome!

What is used for water retention? Rubber liner, clay or concrete?

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[woolly]

Thank-you

There is a liner (plastic I think). I can't be certain what is underneath the liner, I assume earth but it's possible some concrete was put in the deep part when it was built (around 16 years ago I believe).

 

[MitchM]

I don't see any problem with reducing the pond size.
Lower the water level to empty the area that you wish to fill in, lift up the liner and backfill behind it.
Make sure that you maintain proper living conditions for the fish.
Adjust the water flow and filtering as necessary.

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[woolly]

Hi Mitch
So would you suggest just filling in the shallow part? It seems like that is the easiest and requires least materials, we had just wondered whether to fill in some of the deep part as we don't actually use it for 'swimming' in. I'll probably get someone in to do it for me anyway, with 2 jobs and 2 pre-school kids we barely have time to manage the garden maintenance never mind any bigger projects!
Thanks again

 

[MitchM]

I am not saying to just fill in the area you don't want as pond area any more. That would result in a lot of suspended matter in the pond and would plug your filter and result in an algae bloom.
You need to get underneath the liner and fill behind that.
If you want to fill in the deepest part, there should be a redesign of the whole pond.

 

[woolly]

I see, thanks, yes I meant just back-filling in the shallow part (in the foreground in the first pic). On closer inspection I think the deep part (foreground in the second pic) must be a pre-formed piece, so that really would be a much bigger (and more expensive) job. We'll start with the easy bit!

 

[mgmine]

As Mitch says pull the liner and fill in under it. I would leave the deep end if that is the part that is in the right spot in the yard. If not then I would pull the whole liner and dig the pond the way you want it. Spread the newly excavated dirt around and put the old liner back in for a cushion then put in a new liner.

 

[sissy]

You need to find out if the liner is epdm and what condition it is in if you want to save money .If it feels like a rubber on a car tire but thinner it is epdm .If it feels like plastic and tears then it is plastic .If you can cut a tiny piece of it out you could take it to a pond store or just find someone who knows .Taking the whole thing out can be a lot of work and you will need storage for plants and any fish until done .The epdm liners last a long time and are heavy to move .

 

[Mmathis]

Well, what I would do...... First of all, decide "how much" pond you are willing to live with. Decide on a reasonable number of gallons (or litres) and a reasonable size (length & width). I wouldn't worry so much about filling in or not filling in what is there as much as I would plan out what I wanted the end product to be. "Where" do you want pond and "where" do you not want pond?

Your overall depth is going to depend a lot on what your summer and winter temperatures are. You want enough depth that the fish can stay cool in summer and not turn into fishsickles in winter -- that's generally around 3ft or so. Some people have varying depths to their ponds, and some people have only a single depth -- that part is up to you. And take it from there! Chances are you're going to need a lot of fill dirt anyway, so how you build things up can depend on how stable [clay vs sand] your soil is.